Hi Gus,It doesn't matter how many old trucks you have, or have had, we are talking about buses here. As Kyle pointed out , at least some buses were available with either graesed or differential oil lubricated bearings. Our GM 4106 has differential oil lubricated bearings. It requires a different seal for each type of lubricant so when servicing the bearings be sure to get the right seal.It really is great that this board is available so that, if we pay attention, we can all learn something new. Since you no doubt have the maintenance and parts manuals for your coach, perhaps if you look at them you can verify what several people have been trying to teach you. Learning should be a lifelong endeavor.Good luck, Sam 4106

Like TomC. I've always worked with axles that were wet, (oil lubed from the differential), and I took for granted that my hubs were wet lubed also. But I got to thinking about what Gus said so I got out my maintenance manual and turned to section 13 where there is a drawing of the bus with all the lubrication points.

Low and behold, my hubs, both front and rear are hand packed with grease. So now I have one more yearly maintenance task to perform..... packing the wheel bearings in the rear.

Thanks Gus, I would have argued all day long that my differential was the same lube system that was on my trucks. I think you may have saved me and possibly a few others from a costly failure.

All I can say is, everyone, get out your maintenance books and look it up to be certain you are doing the correct thing!

Laryn, just check your maint. or parts manual. Or better yet, pull an axle sometime. It doesn't take too long. And you can take a look at your bearings that way. Despite Sam 4106's comment, I'm pretty sure all v-drive GMC parlor coaches have grease-packed rear bearings separate from the oil diff. lube. Seals (should) keep everything isolated. In fact, the fill line of the diff. should give some clue as well, since i'd have to be parked on a really steep side grade to get oil to even run down my axle tubes.

Here's a pic taken last month of my RR hub after packing it and setting the outer nut, but before I cleaned it up, put the seals on, and put the axle back. The red stuff is synthetic bearing grease.

CoolÖ.No one documents better than you Brian. Being able to see what was done, in addition to just reading about it, makes all the difference in the world. So, now that you have done it, how would you rate the difficulty of inspecting and repacking the rear bearings? Are new seals required or recommended every time itís done? How long should it take to perform this preventive maintenance? Any special tools required?

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Laryn, I know I could do the other side in a fraction of the time. I have never done anything like this before, and knew next to nothing about how the rear axles and hubs of a "big rig" go together. Every bus project of mine seems to be a new experience for me!

It took me a long time to get the drum off due to the rust. I ended up getting a hex head drive from Sears and used a small impact and some torch heat (and a LOT of PB Blaster) to get them free.

Check the book, but if the seals are in good shape, they should be able to be re-used, although I'd go ahead and get new axle seals as cheap insurance. I also got new axle nuts, since I boogered up the outer one getting it off. John Z., NAPA sells the thin-walled 4" socket (About $30), but it likes to slip off when hogging down on it. I had to use the 1" impact to tap it off. Return springs on the shoes were a big pain for me, also, since I didn't have the proper curved tool.

If you've done this sort of heavy work before, and have the right tools, I'd think it is easily doable in a day, assuming you don't find something else to replace, like a shock or the air bellows. Once you have the duals off, you might want to "kill a lot of birds" under there!

The axle nut wrench is a cheap sheet metal tool available at most truck supply houses. Measure the nuts on your axle and get the exact size. The inner nut is only tightened enough to preload the bearings (the tricky part) and then the lock washer is put between the nuts. You may need a new lock washer if the old one has been bent over too many times. With the lock washer in place it is not necessary to excessively tighten the lock nut. Done properly, you will never wear out the cheap wrench.

Hi Brian,You are painting with a pretty broad brush when you state that "...all v-drive GMC palor coaches have grease-packed rear bearings...". Had you said that all v-drive GMC parlor coaches ORIGINALLY had grease-packed rear bearings that would have been more believeable, although you still would be painting with a broad brush. My GM 4106 MAY NOT have had differential oil lubricated bearings ORIGINALLY but it has had since I have had it (18 years).I was in my pit readjusting my brakes, after a recent brake job, when I discovered a leaking wheel seal. Since I was just replacing a rear seal, I didn't remove the drum from the hub. I used my cheery picker, with the boom extended, to pick up the whole unit by wraping a chain around the drum. I got the new seal from the local bus company. It was for a MCI-9 but the number matched, which leads me to believe that MCI-9s also have differential oil lubricated rear bearings. To be sure differential oil filled the hub after everything was back together I simply overfilled the differential.I also made my own wrench out of 1/4" flat iron to fit the 4" nuts.I think Dallas put it well: "The things we learn when we least expect it.". Your milage may vary.Good luck, Sam 4106

Okay guys, I've read enough, you've scared the #$%^ out of me.... I'm having all wheel bearings and brake hardware inspected before I depart Phoenix for Gulfport, Miss. Anything else I should have looked at, while the wheels are off.

Know any good shops in Phoenix? Has anyone dealt with All Aboard America in Mesa, Az? Any shops to stay away from?